1. Field
One or more embodiments relate to a developing unit adopting a two-component developing agent including a toner and a magnetic carrier, and an image forming apparatus employing the developing unit.
2. Description of the Related Art
In electrophotographic image forming apparatuses, an electrostatic latent image is formed on a surface of a photosensitive body by scanning light that is modulated according to image information onto the photosensitive body, the electrostatic latent image is developed into a visible toner image by supplying toner to the electrostatic latent image, and the toner image is transferred to a recording medium and fused thereto so that an image is printed on the recording medium.
The electrophotographic image forming apparatuses may use a one-component developing type using a one-component developing agent containing a toner, or a two-component developing type using a two-component developing agent, in which a toner and a carrier are mixed, and developing toner only onto a photosensitive body.
In an image forming apparatus of the two-component developing type, a thickness of a developing agent attached to an outer circumference of a developing roller is regulated by a regulation member that is a predetermined distance apart from the outer circumference of the developing roller. In order to obtain printing images of high quality, a thickness of the developing agent layer that is supplied to a developing region where the developing roller and a photosensitive body face each other has to be uniform in an axial direction of the developing roller. If the thickness of the developing agent layer is not uniform, smudges in image concentration and dispersion of the toner may occur. Also, if a developer mass per area (DMA) on the surface of the developing roller is excessively changed within a lifespan period of the developing agent, wherein the developing agent is regulated by the regulation member and supplied to the developing region, stable image quality may not be maintained.